Speed responsive apparatus



Dec. 28, 1937. `H L BONE 2,103,706

SPEED RESPONSIVE APPARATUS Filed May 17, 1935 i v 7 /rornrra rma/v 3 a 33 arr/mvg MEMBER 193 .S/.ow plc/rap 510W Plc/rap .P5 *..Iyfyzf Patented Dec. 28, 1937 UNITED STATES PATENT OFFICE SPEED RESPONSIVE APPARATUS Application May 17,

11 Claims.

My invention relates to speed responsive apparatus.

An object of my invention is the provision of novel and improved speed responsive apparatus 5 which is actuated by electrical means, and by which an unsafe indication due to loss of power or breakage of a part is avoided.

Speed responsive apparatus embodying my invention is particularly suitable for, although in no way limited to, use in connection with speed control systems for railway trains.

I will describe several forms of apparatus embodying my invention, and Will then point out the novel features thereof in claims.

In the accompanying drawing, Fig. 1 is a diagrammatic View illustrating one form of apparatus embodying my invention. Fig. 2 is a diagrammatic view of a second form of apparatus embodying my invention, and Figs. 3 and 4 are 2O diagrammatic views of modifications of the apparatus of Fig. 2 and Which also embody my invention.

Similar reference characters refer to similar parts in each of the several views. g5 Speed responsive apparatus embodying my invention embraces a suitable speed responsive circuit interrupting means and a time limit electromagnetic means adapted to come into action a short period after the conditions actuating it Q have begun to exist. As shown in Fig. 1, the circuit interrupting means is a commutator, designated as a Whole by the reference character Cl, and the time limit electromagnetic means consists of two relays Rl and R2 of the direct current ,3 neutral type. The shaft i of the commutator Cl is operatively connected with a member the speed of whose movement it is desired to determine through the medium of any suitable drive mechanism such, for example, as a train of gears not shown. When the apparatus is utilized to control the circuits of a speed control system for railway trains, the shaft I is preferably operatively connected with an axle of the vehicle on which the apparatus is mounted, with the result that the speed of rotation of shaft l is in accordance with the speed of the railway train. A contact brush 2 is rigidly mounted on the shaft l for rotation therewith and is adapted to engage three annular segments 3, 4 and 5, the arrangement being such that the segment 3 is a complete ring and ccntinuously engages the brush 2, but the segments and 5 span only a little over 180 and alternately engage the brush 2. It follows that with the shaft l stationary, electrical connection is continuously completed between the segment 3 and CYS 1935, Serial No. 22,029

(Cl. 17E- 355) one or the other of the segments 4 or 5, depending upon the position of the contact brush 2, but that with the shaft I rotated, electrical connection is alternately completed between the segment 3 and the segments 4 and 5, the duration which the connection is completed in each case being dependent upon the speed of rotation of the shaft l, and hence, in turn, dependent upon the speed of the driving member. It is to be understood, however, that my invention is not limited to any specific form of circuit interrupting means and the commutator CI is shown for illustration only. It is clear that the commutator CI may be constructed with the segments 3, 4 and 5 mounted rigid on the shaft l for rotation therewith, and the contact brush 2 held stationary should it seem desirable to do so.

The commutator CI controls the energizing circuits for the relays RI and R2, thearrangement being such that the circuits are alternately opened and closed with rotation of the shaft I The segment 3 is connected over wire 6 with one terminal of any convenient source of direct current such as a battery l, and which battery is preferably of a predetermined given voltage. The other terminal of battery is connected with one terminal of the operating winding of each of the relays RI and R2 over wires 8 and 9, respectively. The second terminal of the operating winding of relay RI is connected over wire l0 with the segment 5, and the second terminal of the operating winding of relay R2 is connected over wire il with the segment 4. Consequently, when brush 2 is in the position to engage the segment 4, current flows from the battery 1 over wire G, segment 3, brush 2, segment 4, wire Il, operating Winding of relay R2, and wire 8 back to the battery 1, and the relay R2 is energized, the potential difference across the terminals of the relay R2 being substantially the full voltage of the battery 1 since the ohmic resistances of wires 6, 8 and Il, and the contact resistance of brush 2 with segments 3 and 4 are negligible. When the brush 2 is moved around and engages the segment 5, current flows from the battery 'l over Wire 6, segment 3, brush 2, segment 5, wire I0, operating winding of relay RI, and Wire 9 back to the battery l, and relay RI is energized, the potential difference across the terminals of the relay Rl being substantially the full voltage of the battery 'l since the ohmic resistance of the circuit other than that of the operating winding of the relay is negligible. When the brush 2 is rotated in response to rotation of shaft l, the relays Rl and R2 are alternately supplied with current, the duration of each current impulse being in accordance with the speed of rotation of shaft I. It is to be noted that at least one of the relays RI and R2 is always supplied with current whatever the position of brush 2, since the segments li and 5 are made to slightly overlap, as explained hereinbefore. When the brush 2 is in a horizontal position, as Viewed in Fig. 1, both relays are supplied with current in parallel.

'Ihe relays RI and R2 are each provided with a circuit controlling armature in the usual manner, the armature I2 of relay RI being adapted to be raised into engagement with a front contact I3 when the relay is energized, and to drop out of engagement therewith when the relay is deenergized. In like manner, the armature I4 of relay R2 is adapted to be raised into engagement with a front Contact I5 when the relay is energized, and to drop away from engagement therewith when the relay is deenergized.

As set forth hereinbefore, the relays RI and R2 constitute a time limit electromagnetic means adapted to come into action a short period after the conditions actuating it have begun to exist, and to this end, each relay RI and R2 is provided with slow pick-up characteristics. That is to say, the armature I2 of relay RI, for example, is not raised into engagement with the front Contact I3 until a predetermined time interval subsequent to initiating the energization of the relay by supplying current to its operating Winding.` Likewise, the armature i4 or" relay R2 is not raised into engagement until a predetermined time interval subsequent to initiating energization of that relay by supplying current to its operating winding. In other words, the relays RI and R2 each become effective to operate its respective armature a short period after current is initially supplied to the operating winding of the relay. The time delay in operating the armature is preferably the same for both relays RI and R2. Such time delay in pick-up may be accomplished in any convenient manner, several arrangements being Well-known in the art for providing a direct current relay with slow pickup characteristics.

In addition to being provided with slow pick-up characteristics, the relays RI and R2 are each provided With relatively high pick-up characteristics. For example, the relay RI is so proportioned and adjusted that the tractive effort necessary to raise the armature I2 into engagement with the front contact I 3 is produced when the value of a current flowing in its winding is, say, r75% of the ultimate current value resulting from a potential difference across the terminals of the relay equalto the full voltage of the battery l. Likewise, the pick-up current of relay R2 is approximately '75% of the ultimate current effected when the full voltage of the battery 'I is impressed across the terminals of the relay. The relays RI and R2 possess two constants-resistance and inductance. Due to inductance, the current resulting from a voltage impressed across the terminals of the operating winding does not at once rise to the value ultimately reached, that is, the value as indicated by Ohms law. It follows that with the brush 2 stationary at the position illustrated in Fig. l, the relay R2 is supplied with'current the ultimate Value of which is equal to that produced by the full voltage of the'battery l, as determined by the resistance of the relay, since the inductance delays the building up of the current for a relatively short period only.

. Under this condition, the energization of the relay R2 is suicient to attract the armature I4 and raise it into engagement with the front contact I5 at the expiration of the slow pick-up period. If the brush 2 is rotated at a speed such that the time interval the brush 2 makes engagement with the segment 4 during a half revolution is a little greater than the slow pick-up period of relay R2, the armature I4 is raised into engagement with contact I5 during this half revolution of the shaft I since the time constant resulting from inductance is less than the slow pick-up period and the ultimate value of the current as indicated by Ohms law is eifected for a sufficient length of time. During the half revolution the brush 2 breaks engagement with the segment 4, the energization of relay R2 dies away to substantially zero and the armature I4 is released. Hence, at such speed of shaft I the relay R2 is picked up and released once each revolution of the shaft I.V In the event the brush 2 is rotated at a speed such that the duration of the connection between, the segments 3 and LS by brush 2 is slightly less than the slow pick-up period of relay R2, the armature I 4 remains down out of engagement with the contact I5. Under this condition of speed, the time interval between two successive impulses is suicient for the energization of the relay to die away to substantially zero, notwithstanding the inductance causes a slight delay in the dying away of the current. Again, if the speed at which the brush 2 is rotated is relatively high, and rapid impulses of current are supplied to the winding of relay R2 and build up the magnetism in the magnetic circuit, the average value of the current flowing in the operating Winding, however, does not reach the '75% pickup value due to the inductance of the relay, and hence the armature I4 is not raised into engagement with Contact I5 at such relatively high speeds. In other words, there is a critical speed above which the relay R2 is not picked up, and below which the relay is alternately picked up and released, while at zero speed the relay is steadily energized in case the brush 2 stops at a point where it makes engagement with the segment 4, and the relay is deenergized in case the brush 2 stops at a point where it is out of engagement with the segment 4.

Since the relay RI is proportioned and adjusted similar to relay R2, the operation of the relay RI in response tothe different speed conditions of brush2 is the same .as just explained in connection with relay R2, except for the fact that the circuit for the relay RI is governed during the opposite half revolution of brush 2, rIhe speed of shaft I below which the relays RI and R2 are picked up is hence determined by the pick-up time provided for the relays. For eX- ample, if it is desired to operate the relays RI and R2 at speeds up to ten revolutions per minute of the shaft I, that is, one revolution every six seconds, the pick-up time would be three seconds since each relay is energized during'one-half of each revolution. Thus, at all speeds below ten revolutions per minute, each relay would be picked up While its circuit is closed by the brush 2, but that at all speeds above ten revolutions per minute both relays would remain down. At zero speed one or the other of the relays RI or R2' would be picked up, and in the case the brush 2 should stop at the horizontal position, as viewed in Fig. l, both relays would be picked up.

The relays RI and R2 may be utilized to control indication and control .devices to determine Whether or not the driving member is moving at all, or is moving above or below a predetermined critical speed. As here shown, relays RI and R2 govern an indication lamp I8 and a control magnet I8 by virtue of two simple circuits, both of which circuits include a battery I1 and one of which includes the contact I2|3 of relay RI and the other of which includes the contact |4-I5 of relay R2. Hence, the lamp I6 is steadily illuminated and the control magnet I8 is steadily energized when the speed of shaft I is zero, since at zero speed at least one of the relays RI or R2 is steadily picked up. When the speed of shaft I is not zero but is below the critical speed, and the relays are alternatelypicked up and released, the lamp I6 is flashed and the magnet I8 is intermittently supplied with current. When the speed is above the critical speed and neither relay is picked up, the lamp I6 is dark and the magnet |8 is deenergized. As here shown, the magnet I8 is provided with slowrelease characteristics, and hence is energized at zero speed and at speeds below the critical speed. When the apparatus of Fig. 1 is used in connection with speed control systems for railway trains, the lamp I6 may be used to indicate to the operator of the train the zero and low speed conditions, and the magnet I8 may be used to effect a control over the train brake equipment, and when so used an unsafe indication due to loss of power or breakage of a part is avoided.

In Fig. 2, the circuit interrupting means is in the form of a double commutator indicated as a whole by the reference character C3, and the time limit electromagnetic means consists of a single direct current relay R3. Two contact brushes 24. and 25 are mounted rigid on the shaft I, here indicated schematically by a dotted line, the brush 24 being adapted to make engagement with a segment 26 continuously and with segments 2l and 28 during alternate half revolutions, and the brush 25 being adapted to make engagement with a segment 29 continuously and with segments 38 and 3| during alternate half revolutions. One terminal of the battery is connected with the segment 26 over wire 36 and the opposite terminal of the battery is connected with the segment 2S over wire 3T, and thus the brush 24 is electrically connected with one pole of the battery and the brush 25 is connected with the other pole of the battery. The right-hand terminal of the winding of relay R3 is connected with the two segments 27 and 30 over wires 32 and 33, respectively, and the left-hand terminal of the winding of relay R3 is connected with the two segments 28 and 3| over wires 34 and 35, respectively. It follows that with the brushes 24 and 25 in the position illustrated in Fig. 2, current is supplied from the battery 'I to the winding of relay R3 over wire 35, segment 26, brush 24, segment 2l, wire 32, operating winding of relay R3 wire 35, segment 3|, brush 25, segment 29, and wire 3l back to the battery; but that with the brushes 24 and 25 rotated 189 from the position illustrated, current is supplied from battery 'I over wire 36, segment 26, brush 24, segment 28, wire 34, operating winding of relay R3, wire 33, segment 3D, brush 25, segment 29, and wire 3'| back to the battery. It is to be noted that in the rst case where brushes 24 and 25 engage segments 21 and 3| the current flows through the operating winding of relay R3 in one direction, while in the second case where brushes 24 and 25 engage segments 28 and 38 the current flows through the operating winding of relay R3 in the opposite direction. That is to say, during one-half revolution of the shaft i, the relay R3 is energized with current of one polarity and during the second one-half of the revolution the relay R3 is energized with current of the opposite polarity, with the result that the magnetization of the relay R3 builds up in one direction, dies away to zero, builds up in the opposite direction and dies away to zero each revolution of the shaft I. The relay R3 is provided with siow pick-up characteristics similar to the relays Ri and R2, but the pick-up value of current for the relay R3 need not be relatively high as was the case in connection with relays Rl and R2. Consequently, at zero speed of shaft I the relay R3 is retained steadily picked up; at speeds below the critical speed the relay R3 is alternately picked up and released since the duration of each impulse is greater than the slow pick-up period, and since the polarity of energization of the relay is reversed each half revolution; but that at speeds above the critical speed and when the duration of each impulse is less than the pick-up period, the contact 39-40 of relay R3 remains open. At relatively high speeds of shaft I the magnetization in the magnetic circuit of relay R3 is not slowly built up by the rapid successive impulses since the magnetization of the relay is reversed each half revolution. The relay R3 governs the indication lamp I5 and the control magnet I8 by a simple circuit which includes the contact 39-40 of the relay. It is clear, therefore, that the lamp i6 and magnet 5S of Fig. 2 are governed in response to the speed of rotation of shaft I in a manner similar to that explained in connection with Fig. l, and an unsafe indication due to loss of power or breakage of a part is avoided.

In this form of apparatus a snap action of the contact brushes 24 and 25 from engagement with one associated segment to the other segment is provided. Looking at brush 24, for example, its outer end 24a is pivoted at S5 to the inner end 24b which is rigid on shaft I. rShe outer end 24a is held in a central position by means of two flat springs Si and. 9S, the inner ends of which springs are riveted at 99 tothe inner end 241 of brush 24. It is clear that the outer end 24a of brush 24 may be turned in either direction about the pivot 96 against the force of spring 97 or 98 depending upon the direction it is turned. Assuming the shaft I is rotated ccnnterclockwise, as viewed in Fig. 2, the outer end 24e strikes a stationary post |38 and is turned about the pivot 9G against the spring 98. In such position against post |08 the brush 24 is held in engagement with the segment 2l'. Upon further rotation of shaft I and the inner end 24O of brush 24, the outer end 24EL is turned until it slides past the post |89 and when that position is reached the outer end 24e is snapped back to its central position due to the force of the spring 98, and the brush then makes engagement with the segment 28. It is seen therefore, that brush 24 is snapped from engagement with segment 2'! to engagement with segment 23 and that shaft i can not stop at a position where brush 24 engages both segments 27 and 28 at the same time or where it is not in engagement with either segment. When the shaft I has rotated one-half revolution and brush 24 encounters a stop post itI, a similar snap action of brush 24 from engagement with segment 28 to engagement with lsegment 2l takes place. The brush 25 is constructed in a manner similar to that just described for brush 24 and has associated therewith two stop posts |02 and |03 and a snap action of brush 25 from engagement with segment 3l to engagement with segment 39 or Vice versa is accomplished.

In the form of the invention disclosed in Fig. 3, the time limit electromagnetic means consists of two relays R and R5, each of which is provided with slow pick-up characteristics similar to relay R3. The circuit interrupting means of Fig. 3 consists of a commutator C5 which includes two brushes 4l and 32 rigid on the shaft l, and two pair of annular segments associated with each brush. The brush ffii, in addition to continuou-,sly engaging a segment 33, alternately engages the individual segments of both pair of segments, the first pair of which consists of segments 4d and 45, and the second pair of which consists of segments it and M, as will be readily understood by inspection of Fig. 3. In like manner, the brush 42, in addition to continuously engaging a segment 58, alternately engages a ilrst pair of segments i9 and 5@ and also alternately engages a second pair of segments 5I and 52. The battery 'I has its two terminals connected with the segments i3 and 33, respectively. The opposite terminals of the winding of relay Rit are connected with the segments te and Q5 of the first pair associated with brush il over wires 53 and 55, respectively; and are also connected with the segments i9 and 55 of the first pair associated with the brush i2 Vover wires 55 and 56, respectively. In a similar manner, the opposite terminals of the winding of relay R5 are connected with the segments lt and di of the second mentioned pair associated with the brush 4I over wires 5l and 58; and are connected with the segments 5! and 52 of the second mentioned pair associated with the brush @2 over wires 59 and 60. It follows that with the brushes il and 42 in the position illustrated in Fig. 3, current of one polarity is supplied to the relay R4, but that with the brushes moved around 180 from the position illustrated, current of the opposite polarity is sup-plied to the relay R5. The first circuit may be traced from the battery 'i over segment 43, brush 4l, segment Q5, wire operating winding of relay Ri, wire 56, segment 50, brush 42, segment it and back to the opposite terminal of the battery l; and the second circuit may be traced from battery l over segment 43, brush fil, segment lili, wire 53, operating winding of relay Rd, wire 55, segment 4S, brush 52, segment G8 and back to the battery l. In a like manner, `current of one polarity is supplied to the winding of the relay R5 with the brushes il and 42 in the position illustrated, and is supplied with current of the opposite polarity when the brushes t! and i2 are rotated 180. In this case, the rst circuit includes battery "i, segment llt, brush 4i, segment dil, wire winding of relay R5, wire 69, segment V52, brush 2, segment 48 and to the opposite terminal of the battery; and the second circuit includes battery l, segment 43, brush l l, segment @6, wire 5l, operating winding of relay R5, wire 59, segment 5i, brush d2, segment i8 and back to the battery l. It is to be noted that the brushes @l and G2 pass from one segment to the next of one pair of the segments 90 in advance of the point where they pass between the two segments of the other pair. Hence, with the apparatus constructed as shown in Fig. 3, both relays R5 and R5 are steadily picked up at zero speed for all positions of the brushes @l and 42 except at the points adjacent the two segments of a pair of segments, and in this instance at least one of the relays is energized. It follows, therefore, that the relays R4 and R5 are each operated in response to rotation of the shaft I in the manner explained in connection with relay R3 of Fig. 2.

The relays R4 and R5 control the indication lamp i6 and the control magnet I8 by two simple parallel circuits, one of which includes the circuit controlling armature 92 of relay R4 and the other of which includes the circuit controlling armature 93 of the relay R5, with the result that the indication lamp I6 and the control magnet i8 are governed by the apparatus of Fig. 3 in exactly the same manner as explained for the previous forms of the invention, and an unsafe indication due to loss of power or breakage of a part is avoided.

In Fig. 4 the circuit interrupting means consists of a cam 'i3 rigid on shaft i and a polechanging circuit controller C5, and the time limit electromagnetic means includes the relay R3 the same as the apparatus of Fig. 2. The cam 'i3 is provided with a raised portion l@ and adepressed portion l5, each of which spans slightly less than 180, and the two portions are joined together by easy sloping surfaces 'l5 and Ti. The cam follower 'iS is biased to ride on the surface of the cam by a spring l5 as well as by its own weight. The cam follower ES is adapted to operate the contact controlling members and 8i of the controller C5, the arrangement being such that with the cam follower i3 in engagement with the raised portion 14 of the cam '53, the contact members S and 3l are raised into engagement with front pole-changing contacts 82 and 83, respectively; but that when the cam follower i8 engages the depressed portion l5 of the cam i3, the contact members 80 and Si are down in engagement with the back pole-changing contacts 84 and S5, respectively. The contact members 88 and 8l are actuated by the cam follower 'i8 by virtue of pins and 87 adapted to t slightly elongated slots in the cam follower, and the contact members 8? and 8l are provided with compression springs 83 and 89 which are secured to the outer end of the Contact members and are fixed at the points 9@ and 55, respectively. It is to be seen, therefore, that as the cam follower 'l5 rides up or down one of the sloping surfaces TS or "il, as the case may be, and the contact members 8@ and 8l are actuated from one position toward the second position, the springs 88 and 8S are rst compressed and then are effective to act as toggle springs to snap the contact members to the position toward which they are being moved when the mid position is reached with the result that should the shaft i stop at a position where the cam follower engages one of the surfaces 'it or il, an open position of the contacts is avoided. The battery i is connected to the contact members Sii and 8i, and the opposite terminals of the winding of relay R3 are connected with the pole-changing contacts StL-S-i-t in the usual manner, with the result that the relay R3 is energized with current of one polarity during one-half revolution of the shaft l and is then energized with current of the opposite polarity during the other half revolution of the shaft l. It follows that the relay Rffof Fig. 4 is steadily picked up at zero speed of the shaft is alternately picked up and released at speeds below the predetermined critical speed, and its armature 9i is released for all speeds above the critical speed. The control circuit for the indication lamp i6 and the control magnet i8 includes the armature 9| of relay R3, and hence these devices are governed by the apparatus of Fig. 4 in the same manner previously described for the earlier forms of the apparatus.

The several forms of speed responsive apparatus such as are here provided are each effective to actuate indicating means by simple and rugged electrical circuit devices and an unsafe indication due to a loss of power or breakage of a part is avoided.

Although I have herein shown and described onlyr certain forms of speed responsive apparatus embodying my invention, it is understood that various changes and modifications may be made therein Within the scope of the appended claims Without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

1. Speed responsive apparatus comprising a member adapted to be rotated at different speeds, circuit controlling mechanism operated by said member and including a first pair of contacts closed during a first predetermined porti-on of each rotation of the member and a second pair of contacts closed during a second predetermined portion of each rotation of the member, a current source, a time limit electromagnetic device including an energizing winding; a first control circuit including the source, said winding and said first pair of contacts for energizing said device with current of one polarity; a second control circuit including the source, said winding and the second pair of contacts for energizing the device with current of the other polarity; and an operating circuit including a Contact operated by said device.

2. Speed responsive apparatus comprising a shaft adapted to be rotated at different speeds, a commutator mounted on said shaft, a pair of contact brushes effective to successively engage the segments of said commutator in response to rotation of the shaft, a source of current, a time limit electromagnetic device; a first control circuit including the source, a winding of the device and said brushes for supplying an impulse of current of one polarity to said device during a rst predetermined portion of each rotation of the shaft; a second control circuit including the source, said winding and said brushes for supplying an impulse of current of the other polarity to said device during a second predetermined portion of each rotation of the shaft; and an indication circuit governed by said device and including a contact operated in response to an impulse of current of at least a predetermined duration.

3. Speed responsive apparatus comprising a shaft adapted to be rotated at different speeds, a commutator mounted on said shaft, a pair of contact brushes eifective to successively engage segments of the commutator in response to rotation of the shaft, a source of current, a relay provided with slow pick-up characteristics; a first control circuit including the source, a winding of the relay and said brushes for creating a magnetic field of one polarity for said relay during one predetermined portion of each rotation of the shaft; a second control circuit including the source, said relay Winding and the brushes for creating a magnetic field of the other polarity for said relay during a second predetermined portion of each rotation of the shaft; and an indication circuit governed by said relay and including a contact operated in response to energization of the relay of one or the other polarities for a duration equal to the pick-up period of the relay.

4. Speed responsive apparatus comprising a Shaft adapted to be rotated at different speeds, a commutator mounted on said shaft including a plurality of segments each of a predetermined length, a pair of contact brushes effective to successively engage segments of the commutator in response to rotation of the shaft, a source of current, a pair of slow acting relays; a first control circuit for each relay each of which circuits includes the source, a winding of the relay and said brushes for creating a magnetic field of one polarity for that relay during one predetermined portion of each rotation of the shaft; a second control circuit for each relay each of which circuits includes said scurce, the winding of the relay and said brushes for creating a magnetic field of the other polarity for that relay during a second predetermined portion of each rotation of the shaft; and an operating circuit governed jointly by said relays and including a contact of each relay operated in response to energization of the relay of one or the other polarities for a duration equal to the slow acting period of the relay.

5. Speed responsive apparatus comprising, a member adapted to be rotated, circuit controlling mechanism operated by said member and including a first pair of contacts closed during a first predetermined portion of each rotation of the member and a second pair of contacts closed during a second predetermined portion of each rotation of the member, a current source, a slow pick-up relay; a first control circuit including the source, a winding of said relay and said first pair of contact for energizing said relay with current of one polarity; a second control circuit including the source, a winding of said relay and said second pair of contacts for energizing said relay with current of the other polarity; and an operating circuit including a front Contact of said relay.

6. Speed responsive apparatus comprising a member adapted to be rotated, circuit controlling mechanism operated by said member and including a first Contact closed only during a rst por-v tion of each rotation of said member and a second contact closed only during a second predetermined portion of each rotation of said member, a current source, a slow pick-up relay; a first control circuit including the source, a winding of said relay and the first contact and effective to create a magnetic field of one polarity for said relay; a second control circuit including the source, a winding of said relay and the second contact and effective to create a magnetic field of the other polarity for said relay, and an operating circuit including a front contact of said relay.

7. Speed responsive apparatus comprising a member adapted to be rotated, a first contact mechanism operated by said member and closed only during a first predetermined portion of each rotation of said member, a second contact mechanism operated by said member and closed only during a second predetermined portion of each rotation of said member, a current source, a slow pick-up relay, a first control circuit for energizing said relay including the source and said first contact mechanism and effective to create a magnetic field in the relay of one polarity, a second control circuit for energizing said relay including the source and said second contact mechanism and effective to create a magnetic field of the other polarity in said relay whereby said relay is picked up only at substantially zero speed of said member, and an operating circuit controlled by said relay.

n 8. Speed responsive apparatus comprising, a member adapted to be rotated and having formed thereon a raised portion and a depressed portion, an operating element biased to ride on said portions of the member, a first pair of contacts controlled by said element and closed only when said element rides on the depressed portion, a second pair of contacts controlled by said element and closed only when said element rides on the raised portion of said member, a current source, a slow pick-up relay; a first control circuit including, the source, the winding of the relay and said first pair of contacts to energize the relay with current of one polarity; a second control circuit including the source, the Winding of the relay and said second pair of contacts to energize the relay with current of the other polarity whereby said relay is picked up only at substantially zero speeds of said member, and an operating circuit controlled by said relay.

9. Speed responsive apparatus comprising a member adapted to be actuated through an operating cycle at different speeds, circuit controlling mechanism operated by said member and including a rst Contact closed during a fixed portion of each cycle and a second Contact closed during substantially the remaining portion of each cycle, an electroresponsive device including a contact which is operated a predetermined time interval subsequent to initiating energization of said device, a iirst control circuit including a current source and said first contact of said mechanism for energizing said device with current of one polarity, a second control circuit including a current source and said second Contact of said mechanism for energizing said device with current of the opposite polarity; whereby energization of said device by current of one polarity is initiated, this energization is reduced to zero and energization of the device by current of the opposite polarity is initiated during each cycle of operation of said member; and an operating circuit including the contact of said device when operated.

10. Speed responsive apparatus comprising a member adapted to be actuated through an operating cycle at dilerent speeds, circuit controlling mechanism operated by said member and including a rst contact closed during a lirst predetermined portion of eachY cycle and a second contact closed during a second predetermined portion of each cycle, a current. source, Va relay ;.a rst control circuit including the source, a winding of said relay and the irst contact of said mechanism and eiiective to create a magnetic eld of one polarity for said relay; a second control circuit including the source, a winding of the Yrelay and the second contact of said mechanism and effective to create a magnetic eld of the reverse polarity for said relay, and an operating circuit including a contact operated by said relay.

11. Speed responsive apparatus comprising a member adapted to be actuated through an 0perating cycle at diierent speeds, circuit controlling mechanism operated by said member and including a rst contact closed during a predetermined portion of the cycle and a second contact closed during substantially the remaining portion of the cycle, a current source, a relay; a rst control circuit including the current source, a winding of the relay and the rst contact of said mechanism and effective to create a magnetic field of one polarity for said relay; a second control circuit including the source, a Winding of the relay and the second contact of said mechanism and effective to create a magnetic eld of the opposite polarity of said relay, and an operating circuit including a contact operated by said relay.

HERBERT L. BONE. 

